Laws of Motion
(Class 9) Chapter 1- Laws of Motion [Notes]
Q1. Match the first column with appropriate entries in the second and third columns and remake the table.
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Q2. Clarify the differences .
1. Distance is the length of the actual path followed by a body between the point the points under consideration.
2. it does not have direction.
3. It's magnitude is greater than or equal to that of displacement .
1. Displacement is the shortest distance from the initial point to the final point of movement of a body .
2. It has direction .
3. It's magnitude is less than or equal to that of distance .
Uniform motion -
1. A body is said to have uniform motion when it covers equal distance in very small equal intervals of time .
2. In this case , the speed of the body is constant .
Non-uniform motion -
1. A body is said to have non uniform motion when it covers unequal distance in equal intervals of time .
2. In this case , the speed of the body is not constant .
Q3. Complete the following table.
a.) The minimum distance between the beginning and the end of the motion of the object is called the motion of the object.
b.) deceleration is negative acceleration.
c.) When an object moves smoothly in a circle, its velocity changes at every point.
d.) The total force remains constant during the collision.
e.) The operation of a rocket is based on Newton's third law of motion.
Q5. Give reasons for research.
a) When an object falls to the ground, its acceleration is constant.
Answer -
1) When an object is in free fall, the only force acting on the object is gravity.
2) The energy of an object close to the center of the earth is the same. In other words, an object thrown on free ground has almost the same acceleration.
b) Although action and response are equal in magnitude and inconsistency, they do not eliminate their effects.
Answer -
The action and reaction of oil causes the body to be different. Therefore, since they are equal in size and direction, their effects are not mutually exclusive.
c.) A tennis ball, both moving at the same speed, stops easier than a cricket ball.
Answer -
A tennis ball that is both moving at the same speed is easier to stop than a tennis ball because in this case the tennis ball has a greater mass than the tennis ball and therefore the cricket ball has more power than the baseball. .
d.) It is assumed that the velocity of a stationary object is uniform.
Answer -
The velocities of stationary bodies are said to be invariant because their displacement is zero at rest, so they do not change with time.
=d1+d2+d3/t1+t2+t3
= 18+22+14/3+3+3
=54/9
=6m/s
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